Siemens LMU54 Series - Composite Outside Temperature; Type of Building Construction

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Siemens Building Technologies Basic Documentation LMU54... / LMU64... CC1P7494en
HVAC Products 3 Functions 07.11.2002
• Compensating variable for flow temperature control
The composite outside temperature is a mixture of actual outside temperature and
attenuated outside temperature as calculated by the controller.
The mixture of actual and attenuated outside temperature is dependent on the type of
building construction and is generated as follows:
Selected type of building construction Composite outside temperature
Heavy TaGem = ½ TiAussen + ½ TaGed
Light TaGem = ¾ TiAussen + ¼ TaGed
The composite outside temperature acts on the flow temperature control as the
compensating variable, enabling the flow temperature to adapt to the prevailing weather
conditions.
Also, it acts on the automatic 24-hour heating limit to switch off the heating.
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t
TiAussen
TaGed
TaGem1
TaGem0
Ta
°C
TiAussen Actual outside temperature
TaGed Attenuated outside temperature
TaGem1 Composite outside temperature of light buildings
TaGem0 Composite outside temperature of heavy buildings
• The building’s thermal storage capacity is taken into account
Allows the rate of control to be adapted to the type of building construction.
Depending on the thermal storage capacity of a building (type of building construction),
the room temperature changes at different rates as the outside temperature varies. This
setting adapts the generation of the composite outside temperature to the type of
building construction (also refer to «Attenuated outside temperature»).
Entry («KonfigRg4»):
XXXX XX1X: Heavy building construction. The room temperature responds more slowly
to outside temperature variations
XXXX XX0X: Light building construction. The room temperature responds more quickly
to outside temperature variations
• Heavy building construction: Houses or buildings with thick walls or walls with
outside insulation
• Light building construction: Houses or buildings with thinner walls or light
brickwork
Composite outside temperature
Benefit
Description
Process
Impact
Example
Type of building construction
Benefit
Description
Impact
Type of building construction